From 1ca97bb541a1f5a735e697a8bba763cde3aab452 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 18 Nov 2012 12:50:10 -0500
Subject: [PATCH] new helper: current_user_stack_pointer()
Cross-architecture equivalent of rdusp(); default is
user_stack_pointer(current_pt_regs()) - that works for almost all
platforms that have usp saved in pt_regs. The only exception from
that is ia64 - we want memory stack, not the backing store for
register one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/alpha/include/asm/ptrace.h | 1 +
arch/blackfin/include/asm/ptrace.h | 1 +
arch/cris/include/asm/ptrace.h | 1 +
arch/h8300/include/asm/ptrace.h | 1 +
arch/ia64/include/asm/ptrace.h | 5 +++++
arch/m68k/include/asm/ptrace.h | 1 +
include/linux/ptrace.h | 4 ++++
7 files changed, 14 insertions(+)
diff --git a/arch/alpha/include/asm/ptrace.h b/arch/alpha/include/asm/ptrace.h
index b4c5b2fbb647..fd53c74ac943 100644
--- a/arch/alpha/include/asm/ptrace.h
+++ b/arch/alpha/include/asm/ptrace.h
@@ -72,6 +72,7 @@ struct switch_stack {
#define user_mode(regs) (((regs)->ps & 8) != 0)
#define instruction_pointer(regs) ((regs)->pc)
#define profile_pc(regs) instruction_pointer(regs)
+#define current_user_stack_pointer() rdusp()
#define task_pt_regs(task) \
((struct pt_regs *) (task_stack_page(task) + 2*PAGE_SIZE) - 1)
diff --git a/arch/blackfin/include/asm/ptrace.h b/arch/blackfin/include/asm/ptrace.h
index 10d8641180f2..c42002506a26 100644
--- a/arch/blackfin/include/asm/ptrace.h
+++ b/arch/blackfin/include/asm/ptrace.h
@@ -106,6 +106,7 @@ struct pt_regs {
#define arch_has_single_step() (1)
/* common code demands this function */
#define ptrace_disable(child) user_disable_single_step(child)
+#define current_user_stack_pointer() rdusp()
extern int is_user_addr_valid(struct task_struct *child,
unsigned long start, unsigned long len);
diff --git a/arch/cris/include/asm/ptrace.h b/arch/cris/include/asm/ptrace.h
index 6618893bfe8e..551c081ab62b 100644
--- a/arch/cris/include/asm/ptrace.h
+++ b/arch/cris/include/asm/ptrace.h
@@ -10,6 +10,7 @@
#define PTRACE_SETREGS 13
#define profile_pc(regs) instruction_pointer(regs)
+#define current_user_stack_pointer() rdusp()
#endif /* __KERNEL__ */
diff --git a/arch/h8300/include/asm/ptrace.h b/arch/h8300/include/asm/ptrace.h
index 7468589a128b..6183371d0c93 100644
--- a/arch/h8300/include/asm/ptrace.h
+++ b/arch/h8300/include/asm/ptrace.h
@@ -63,6 +63,7 @@ struct pt_regs {
#define current_pt_regs() ((struct pt_regs *) \
(THREAD_SIZE + (unsigned long)current_thread_info()) - 1)
#define signal_pt_regs() ((struct pt_regs *)current->thread.esp0)
+#define current_user_stack_pointer() rdusp()
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
#endif /* _H8300_PTRACE_H */
diff --git a/arch/ia64/include/asm/ptrace.h b/arch/ia64/include/asm/ptrace.h
index b0e973649cb9..845143990a1d 100644
--- a/arch/ia64/include/asm/ptrace.h
+++ b/arch/ia64/include/asm/ptrace.h
@@ -78,6 +78,11 @@ static inline long regs_return_value(struct pt_regs *regs)
unsigned long __ip = instruction_pointer(regs); \
(__ip & ~3UL) + ((__ip & 3UL) << 2); \
})
+/*
+ * Why not default? Because user_stack_pointer() on ia64 gives register
+ * stack backing store instead...
+ */
+#define current_user_stack_pointer() (current_pt_regs()->r12)
/* given a pointer to a task_struct, return the user's pt_regs */
# define task_pt_regs(t) (((struct pt_regs *) ((char *) (t) + IA64_STK_OFFSET)) - 1)
diff --git a/arch/m68k/include/asm/ptrace.h b/arch/m68k/include/asm/ptrace.h
index 0f717045bdde..a45cb6894ad3 100644
--- a/arch/m68k/include/asm/ptrace.h
+++ b/arch/m68k/include/asm/ptrace.h
@@ -15,6 +15,7 @@
#define profile_pc(regs) instruction_pointer(regs)
#define current_pt_regs() \
(struct pt_regs *)((char *)current_thread_info() + THREAD_SIZE) - 1
+#define current_user_stack_pointer() rdusp()
#define arch_has_single_step() (1)
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index a89ff04bddd9..a3a9d085f932 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -342,6 +342,10 @@ static inline void user_single_step_siginfo(struct task_struct *tsk,
#define signal_pt_regs() task_pt_regs(current)
#endif
+#ifndef current_user_stack_pointer
+#define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
+#endif
+
extern int task_current_syscall(struct task_struct *target, long *callno,
unsigned long args[6], unsigned int maxargs,
unsigned long *sp, unsigned long *pc);
--
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